1. Field of the Invention
The present invention relates to an accelerator which is used to accelerate the polymerization of cyanoacrylates. More specifically, the invention relates to an accelerator for cyanoacrylate adhesives which are accepted currently and widely in various industrial fields. That is, the accelerator of the invention is suitably used as a pretreatment agent for adhering various adherends by using a cyanoacrylate adhesive more quickly or as an efficient post-treatment agent in the gap-filling adhesion or the mounting adhesion.
2. Description of the Related Art
Since a cyanoacrylate adhesive usually consists of one component, is curable at an ambient temperature, and can bond many kinds of material, it is widely used. However, it is not satisfactory because a gap-filling property, consequently, porous materials such as wood are not well bonded therewith, and mounting adhesion is impossible, and blooming is occurred around an adhered portion of an the work piece due to overflowing of the cyanoacrylate.
In order to solve such problems, others have attempted to improve the rate of polymerization of a cyanoacrylate. Therefore, variety of accelerators have been proposed. For example, JP-B-47-8718 discloses a method in which a surface of an adherend is treated with an accelerator solution containing dimethylaniline or/and tris[1-(2-methyl)aziridinyl]phosphine oxide. JP-B-49-12094 discloses a same method and an accelerator solution containing the specific amine, amide or imide. JP-B-51-25441 discloses vinyl ethers or vinylthioethers as accelerators. JP-B-54-19416 discloses N,N-dimethyl-m-toluidine. JP-B-62-12279 discloses a specific surfactant. JP-B-60-24826 discloses methylolurea and melamine, partially alkoxidized or derivatives thereof.
Among these accelerators, amines are especially effective. However, the amines have brought an older problem Accordingly, some method of controlling occurrence of the amine odor or masking the same has been proposed. For example, JP-B-62-29471 discloses a composition composed of N,N-di-lower alkyl toluidine, saccharin and ascorbic acid or isoascorbic acid. JP-A-59-66471 discloses a mixture of an amine compound, a deodorant and a solvent, respectively. Further, other methods attempt to solve the problem by using amines having high-boiling points. For example, JP-A-6-57218 discloses amines in which at least one hydrocarbon group indicated by R of R.sub.3 N is a long-chain hydrocarbon group having from 8 to 24 carbon atoms and JP-A-5-247412 discloses a nitrogen-containing compound having a dimethylaminoethyloxycarbonyl group or a specific tertiary amine.
In these related techniques, however, the efficiency of acceleration and the control of the odor of the amine were inconsistent. That is, a composition having a satisfactory efficiency in acceleration did not satisfactorily control the odor of the amine.
On the other hand, a composition which satisfactorily controls the odor of the amine was unsatisfactory in the efficiency of accelerations, especially curing efficiency.